21193904036591 has 16 divisors (see below), whose sum is σ = 25702329827328. Its totient is φ = 17211381573600.

The previous prime is 21193904036579. The next prime is 21193904036629. The reversal of 21193904036591 is 19563040939112.

It is a cyclic number.

It is not a de Polignac number, because 21193904036591 - 2²² = 21193899842287 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21193904036551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2390465231 + ... + 2390474096.

It is an arithmetic number, because the mean of its divisors is an integer number (1606395614208).

Almost surely, 2^{21193904036591} is an apocalyptic number.

21193904036591 is a deficient number, since it is larger than the sum of its proper divisors (4508425790737).

21193904036591 is a wasteful number, since it uses less digits than its factorization.

21193904036591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4780939382.

The product of its (nonzero) digits is 1574640, while the sum is 53.

The spelling of 21193904036591 in words is "twenty-one trillion, one hundred ninety-three billion, nine hundred four million, thirty-six thousand, five hundred ninety-one".